Improving color of lubricating oils and waxes



Patented June 16, 195? United States Patent() 2 ,890,963

1 i l I r 2 side streams of varying 'viscosities may be taken off dur- 2 ing the distillation from the high boiling oil. While I prefer to add only about 3 to 5 percent of the higher IMPROVING COLOR 0F LUBRICATING OILS boiling fraction to the rafiinate, there is no objection to AND WAXES 5 adding more, since the end result will be the same. Howi y ever, it isnot necessary to add more than 5 percent, fi g f ai% f ggfg f $i;f f:; and the addition of larger amounts will increase the of New Jersey equipment cost and heat load necessary to process a given amount of raflinate.

N0 Dr w g- Application December 1955 10 In alternative forms of the present invention, the gas Ser 556,424 oil bottoms maybe distilled from the heavy oil before 7 l CL solvent treatment, or the oil may be dewaxed prior to 5 C alms I distlllation. In the latter case, the 011 and wax fractions would each be subjected to distillation from the heavy This invention relates to the improvement of color 1 to ff t color improvement f each f ti of hydrocarbon fractions r particularly, to imr p, While any highboiling oil, such as bright stock, may proving the color of oils and waxes derived from the botb d h hi h b ili component f the mixture, toms fraction of a crac ga although the inventloll I prefer to use a residual oil which has value only as a is also applicableto the treatment of other lubricating :Qmpdnent of heavy fuel 11 Th added color bodies fractions. whichthis oil will pick up in the process will not s It has been known for some time that a g versely afifect its value as a fuel oil, so that after use in highly Stable lubricating Oil Boiling between about the process, it may be sold for the same price as if it had F. and 1100 F. may be produced by fractionating the not been [so-used. Thus, in the practice of my new procproducts of catalytic cracking of a V rgin g 011 f0 ess, there is no loss or degradation in value of any of recover a bottoms product boiling above 500 F., and the fractions charged to the process, and the oils and then solve attracting and deWaXing this P The waxes are decolorized at a minimum cost, since the major il so produced is, however, too dark for ready 0 portion of the heat required for distillation would be tomer acceptance, and the wax recovered in the deWaX- required in any event in the separation of the oil into ing step is also elf-color. It has therefore been necesfra tions of difi i yj iti sary, in order to render both oil and wax salable, to In order that those skilled in the art may more fully redistill and/or treat them with clay or other adsorbent appreciate, the nature of my invention and the method material. Such treatments, while effective to improve for carrying it out, the following example is given: the color of the oil and wax to a point where they meet i specifications, involve a not inconsiderable treating loss. E E I In redistillation, f about 3 i0 10 Percent of the A wide-cut gas "oil boiling between 500.F. and 1000 product treated is recovered as a highly colored bottoms F. was catalytically cracked, and the products were fracvaluable only as an ingredient of heavy fuel oil and tionated to yield gasoline, light fuel oil and a bottoms a-light clay treatment is generally necessary in order product boiling over 500 F. The bottoms was then ex to recover products of acceptable color. Even higher tracted with furfural to yield a waxy oil of lubricating losses are incurred in clay treating without redistillation viscosity. This oil had an OD. color of 177, which is due to adsorption of oil and wax constituents: on the too dark to be commercially acceptable. Nineteen parts clay. Furthermore, uneconomically large quantities of of this Waxy oil were then mixed with one part of bright clay must be used to elfect a sufiicient degree of decoloristock and the mixture was vacuum distilled until nineteen zation. parts were taken overhead, equal to the volume of waxy It is an object of this invention to provide a process oil in the mixture. Characteristics of the oil and bright for treating off-c0101 lubricating oils to improve the color, stock before and after this distillation are shown in the while permitting an almost quantitative recovery of the following table: oil so treated. Table I It is a further object of the invention to provide a process for improving the color of the wax content of a Components in Products cracked gas 011. Charge I have found that the foregoing objects may be attained by solvent extracting that fraction of a cracked gas oil Waxy Bright 95% 5% boiling above about 500 F. to remove low V.I. compo- 011 Stock 1111MB Bottoms nents such as aromatics, then adding to the raflinate at least about 3 to 5 percent of a higher-boiling hydrocarbon fraction and distilling the mixture to recover overiii 1, iii head a fraction equal in volume to the raffinate content 024 of the mixture. It has been found that by so pro- 850 11:11:: 344 ceeding, the major part of the color bodies will be left 33; 88, behind in the still bottoms, and the overhead fraction 7 i5?) 18 may be dewaxed to yield a light-colored lubricating oil which may be further processed to separate it into various fractions of different viscosities, as desired, and an s; 2 i gg g gi i 3 2 3; Si a 2g: :3 2:55 improved color paraffin wax which may be made colormg range as the original oiL The maior part i the less by treatment Wlth smiiu amount of clay While color bodies, however, had been removed to yield an the process of the pres ent invention does not entirely n of acceptable colon This on may be dewaxed by ellmmate y fl It does greatly reduce the conventional methods to yield a high V.I., low pour point, and hence reduces the severity of any subsequent finishi 7 lubricating fraction, and a scale wax which may be demg treatment required. Alternatively, of course, mstead 0 oiled to make a fully refined wax in all respects of as of taking the decolorized raflinate over in one fraction, good quality as may be obtained from the wax distillate fraction of crude petroleum, whereas the wax obtained from the waxy oil without treatment in accordance with the present invention is excessively dark in color compared to waxfrom distillate fractions of crude petroleum. If thevirgin gas oil charged tothe crackingoperation is of a type which does not contain any appreciable amounts of wax,such asthe gas oil obtained from a so-called grade A crude, the dewaxing step may be omitted;

While, as stated above, in commercial practice a heavy residual fuel oil fraction would be the preferred heavy component of the mixture, bright stock was chosen for this example for the reason that a change in its color during the distillation ismeasurable, to show that the colorfbodies in the oil charge are retained in the heavy fraction" during distillation. Ifa black heavy oil had been used, it would have been impossible to accurately detect any color change.

While the foregoing description has been limited, for the purposes of example, to the treatment of lubricating oilsderived from a cracked gas oil, the invention is also applicable to the treatment of highly colored lubricating oils derived from any source, provided only that their end. boiling points are low enough so that a higher boiling hydrocarbon may be mixed therewith, and further provided that the color bodies in the oil are high-boiling enough to remain behind in the distillation bottoms. Whether or not the color bodies are of such a nature may easily be determined by conducting a test in accordance with the procedure outlined above. As an example of other oils which may be upgraded color-wise by my invention, oils which have picked up colored contaminants in use may be mentioned. Accordingly, the appended claims should be broadly construed as applying to the processing of any lubricating oils which may be benefited by the application of the invention thereto.

I claim:

e 1 A process for producing lubricating oils which comprises catalytically cracking a gas oil boiling between about 500 F. and 1100 F., segregating from the cracked products the fraction boiling above 500 F., solvent extracting said fraction to obtain an extract rich in low .V.I. components and a raflinate rich in high V.I. components, admixing with said. rafiinate at least 3% of its volume of a hydrocarbon fraction essentially all of which boils above the end boiling point of the raffinate, fractionally distilling the mixture, and recovering an overhead product approximately equal in volume to the raflinate, said product being lighter in color than the raffinate.

2. The process according to claim 1, including the step of dewaxing the said overhead product. i

3. A process for producing waxes which comprises catalytically cracking a gas oil boiling between about 500 F. and 1100 F., segregating a Wax-containing fraction from the cracked products, admixing with said fraction at least 3% of its volume of a hydrocarbon fraction essentially all of which boils above the end point of the wax-containing fraction, fractionally distilling the mixture, recovering. an overhead product approximately equal in volume to the wax-containing fraction, and segregating wax from the overhead product.

4. A process for producing lubricating oils which includes the steps of catalytically cracking a gas oil boiling between about 500 F. and 1100 F., segregating from the cracked products a heavy fraction boiling above 500 F., admixing with said fraction at least 3% of its volume of a hydrocarbon fraction essentially all which boils above the end boiling point of the heavy cracked fraction, fractionally distilling the mixture, and recovering an overhead product approximately equal in volume to the heavy cracked fraction.

5. Theprocess: according to claim 4 including the step of solvent extracting the overhead product, and recovering as rafiinate an oil of improved V.I.

References Cited in the file of this patent UNITED STATES PATENTS 1,125,422 Whitmore Jan. 19, 1915 1,215,732 Snelling Feb. 13, 1917 2,660,552 Blanding Nov. 24, 1953 2,660,553 Knox Nov. 24, 1953 

3. A PROCESS FOR PRODUCING WAXES WHICH COMPRISES CATALYTICALLY CRACKING A GAS OIL BOILING BETWEEN ABOUT 500*F. AND 1100*F., SEGREATING A WAX-CONTAINING FRACTION FROM THE CRACKED PRODUCTS, ADMIXING WITH SAID FRACTION AT LEAST 3% OF ITS VOLUME OF A HYDROCARBON FRACTION ESSENTIALLY ALL OF WHICH BOILS ABOVE THE END POINT OF THE WAX-CONTAINING FRACTION, FRACTIONALLY DISTILLING THE MIXTURE, RECOVERING AN OVERHEAD PRODUCT APPROXIMATELY EQUAL IN VOLUME TO THE WAX-CONTAINING FRACTION, AND SEGREGATING WAX FROM THE OVERHEAD PRODUCT. 